The present invention relates to a filling processing apparatus and method, and more particularly, to a filling processing apparatus and method capable of executing filling processing based on entered figure data while filling processing is not executed on a preset area (hereinafter referred to as a boring processing).
Conventionally, there has been proposed and widely used a graphic display apparatus in which at least apex data of polygons are received to obtain the boundary line data of the polygons and filling processing is executed on the areas divided by such boundary lines with desired colors to achieve a display having both quantitative and qualitative feelings.
The graphic display apparatus having the arrangement above-mentioned can be applied even though the figure to be actually displayed is not a polygon but a figure composed of, for example, circles, irregular curved lines and the like. More specifically, the figure to be displayed is approximately divided to a plurality of polygons, and the filling processing above-mentioned is executed on each of the polygons to achieve a display having both quantitative and qualitative feelings. Now, the description will be made with reference to a block diagram in FIG. 7.
A host processor (not shown) supplies point data to a drawing unit 61, which, in turn, carries out necessary interpolation operations and supplies the interpolation data to a drawing memory 62. Color index data and the like are then written to the addresses concerned. The figure is then visually displayed on a CRT display device or the like 63. The interpolation data generated by the drawing unit 61 are written in a depth buffer 64. There is then supplied to the drawing memory 62 a write enable signal of the frontmost depth data, out of the depth data of the same plane coordinates. Thus, pixel data with hidden surfaces removed are stored in the drawing memory 62.
Accordingly, even for a figure having a relatively complicated shape, the host processor can recognize it as an assembly of a plurality of polygons each having a relatively simple shape, and filling processing can be executed on each of the polygons. Thus, filling processing can be executed on figure having any shaped. When the original figure is simple, the host processor can recognize it as an assembly of a small number of polygons. Accordingly, the entire processing time required can be short. However, when the original figure is complicated, for example when the original figure includes curved lines, it is required that the host processor recognize it as an assembly of a large number of polygons. This results in long processing time required as a whole.
Further, there are instances where, as shown in FIG. 8 (A), a figure in the form of a triangle is to be filled except for a quadrilateral area defined therein, instead of the whole triangular figure. To execute such filling with the graphic display apparatus above-mentioned, it is proposed to recognize the whole figure as an eleven-cornered figure by drawing an imaginary line connecting the intermediate point of an arbitrary side of the triangle to the intermediate point of the corresponding side of the quadrilateral, and to fill this eleven-cornered figure in its entirety. In this case, however, the number of apexes becomes eleven although the original figure has seven apexes. This increases the number of sides for which interpolation operation is to be executed, thereby to lengthen the entire processing time. Further, since the eleven-cornered figure is a concave polygon, this figure cannot undergo simple convex-polygon filling to be executed in a short period of time. Therefore, the entire processing time required is further lengthened.
In FIG. 8 (C), the polygon above-mentioned is divided into two polygons, and a filling processing is executed on each of the polygons thus divided. This is superior to the processing in FIG. 8 (B) in that the number of apexes of the polygon to be processed is decreased. However, the number of polygons to be processed is increased, and concave-polygon filling processing is still applied. As a whole, processing in FIG. 8 (C) takes a processing time subsantially equal to that required for processing as described with respect to FIG. 8 (B).
In FIG. 8 (D), the polygon above-mentioned is divided into four polygons such that all the polygons thus divided are a convex polygon. This is advantageous in that no concave-polygon processing is required. However, the number of polygons to be processed is remarkably increased. As a whole, the processing in FIG. 8 (D) cannot reduce extensively the processing time required. In particular, when the figure not to be filled incorporates curved lines such as a circular, figure the number of polygons to be processed is remarkably increased since the figure is approximated by a polygon. The problem of lengthened processing time is further prominent.
In any of the procedures above-mentioned, when the number of figures not to be filled is increased, the number of apexes of the polygon to be processed or the number of polygons to be processed is accordingly increased. As a whole, the processing time required is remarkably increased.